I. Antimicrobial Drugs
    A.  chemical substances used for chemotherapy to treat infectious diseases.
        1.  Interfere with growth of microorganisms
        2.  Must act within host (unlike disinfectants)
        3.  Effects of host cells and tissues are important
        4.  Ideal antimicrobial drug kills pathogen without damaging host - Selective toxicity.
        5.  Two classes of drugs:
                a.  Synthetic - made entirely in the laboratory
                b.  Antibiotic - made by bacteria and fungi

II.  History of Chemotherapy
    A.  1928 - Alexander Fleming and the discovery of Penicillin
    B. Howard Florey and Ernst Chain - first clinical trials of Penicillin.

III.  Spectrum of Antimicrobial Activity
    A.  Narrow versus broad spectrum

IV.  Modes of action of antimicrobial medicines
    A.  Inhibition of cell wall synthesis
        1.  Mechanisms
        2.  Drugs
            a.  Penicillins and Cephalosporins

    B.  Inhibition of protein synthesis
        1.  Mechanism
        2. Drugs
            a.  Chloramphenicol, erythromycin, streptomycin, tetracyline

    C.  Cytoplasmic membrane disruption
        1.  Mechanism
        2.  Drugs
            a.  Polymyxin B
            b.  Amphotericin B, miconazole, ketoconazole
 
    D.  Inhibition of nucleic acid synthesis
        1.  Mechanism
        2.  Drugs
            a.  Rifamycins
            b.  Quinolones

    E.  Competitive inhibition by antimetabolites
        1.  Mechanism
        2.  Drugs
            a.  Sulfonamides
 
    F.  Antifungals
        1. Mechanism
        2. Drugs
            a.  Polyenes
            b.  Imidazoles and Triazoles
            c.  Griseofulvin

V.  Antibiotic Resistance
    A. Mechanisms of resistance
        1. Destruction or inactivation of the drug
            a.  B-lactamase enzymes
        2.  Prevention of penetration to the target site within the microbe
            a.  tetracyline resistance
        3.  Alteration of the drug's target site
            a.  Mutation of ribosome sequences
    B.  R factors - genes on plasmids which encode for resistance factors.
        1.  Easily transferred between bacterial cells in a population and between different but closely related populations.
    C.  Factors contributing to resistance.
        1.  overuse and misuse of antibiotics
        2.  patient demand for antibiotics for a cold or influenza
        3.  use of antibiotics by immunosuppressed pateints
        4.  failure of patients to follow prescribed treatment
        5.  long-term, low-dose treatment for acne
        6.  use of antibiotics in animal feed
        7.  moving of resistant bacteria to new areas due to world travel.

VI.  Future of Chemotherapeutic agents